Spatio-temporal Quantitative Modeling And Risk Assessment Of The Spread Of The Novel Coronavirus Pneumonia Epidemic

At the end of December 2019,a rare case of viral pneumonia infection occurred in Wuhan.In order to effectively control the epidemic,under the decision and deployment of the Party Central Committee,strict prevention and control measures were quickly implemented across the country: on January 23,2020,Wuhan was closed.Then all parts of the country began to be isolated in communities: each house was allowed only one person who wears a mask to go out with a travel permit at a time,all companies postpone their resumption of work after the holiday,and all entertainment venues were closed.The epidemic is fierce,and it is a more serious epidemic than SARS.It not only led to thousands of deaths,but also brought severe losses to the global economy.Preventing and controlling the infectious diseases has always been an important topic of everyone all over the world,and theoretical analysis and quantitative research on the pathogenesis and transmission characteristics of diseases are of great significance to prevention and treatment.Therefore,this article examines the characteristics of the spread of the novel coronavirus pneumonia epidemic in China,its development trend,and its spread risk from the perspective of time-space measurement and infectious disease dynamics analysis,and attempts to restore the development and change process of the novel coronavirus pneumonia epidemic in China.On the one hand,it simulates and predicts the development trend of infectious diseases and analyzes the law of its spread.On the other hand,it provides a useful reference for the formulation of government prevention and control measures.First,use the real-time data and historical data of the epidemic to analyze the development trend of the novel coronavirus pneumonia epidemic through graphs.Then,carry out dynamic modeling of the novel coronavirus pneumonia epidemic and characterize the effect of prevention and control measures through parameter assignment changes.Next,select several provinces with relatively severe epidemics in China,such as Hubei,Guangdong,Henan,Hunan,and Zhejiang,have used spatial visualization,spatial correlation analysis,and hot spot analysis to study the spatial distribution and transmission characteristics of the novel coronavirus pneumonia epidemic.Finally,based on the gravity model modeling,the influencing factors of the differences in the spatial distribution of epidemics in 30 provincial administrative areas in China and 16 cities in Hubei except Wuhan were discussed.And the risk of overseas input of the epidemic in various provinces and cities in China was assessed later.The main conclusions obtained are as follows:First,the development trend of the epidemic is different in China and abroad.Under strict prevention and control measures,the domestic epidemic situation in China has been well controlled at the end of March.However,in March the epidemic began to spread rapidly abroad,and the United States and Europe became the new epicenters.Second,the characteristics of the spatial distribution of infection cases in all provinces in China are similar,and they all show a tendency of random spread.Infected cases are mainly concentrated in the capital cities of various provinces,more developed cities,such as Shenzhen,and cities with large numbers of people flowing with Wuhan,such as Wenzhou.The “hot spots” of the novel coronavirus pneumonia epidemic are Wuhan,Xiaogan,Tianmen,Huanggang,Ezhou,Huangshi,Xianning,and Xiantao in Hubei Province.There will be also many confirmed cases in the areas surrounding these cities.Third,the factors affecting the difference in the spatial distribution of the epidemic mainly include the flow of people in Wuhan,the distance from each region to Wuhan,the local population,and GDP.Modeling found that when other conditions remain unchanged,the distance from Wuhan and the number of local confirmed cases change in the opposite direction,and for every 1% decrease in the distance from Wuhan,the number of confirmed cases in the region will increase by 1.55-1.58 percentage points.populations with different structures for every 1% increase in the number,the number of confirmed cases in the region will increase by about 0.5%.In addition,the impact of the urban population on the number of confirmed cases is slightly greater than that of the rural population,that is,when other conditions are fixed,the larger the urban population,the more the number of the infected will obviously increase.For every 1% increase in the total GDP,the number of the infected in the region will increase by about 0.29%.Every 1% increase in the proportion of migrant population from Wuhan to the total number of migrants will increase the number of confirmed cases in the region by about 0.26 percentage points.Fourth,after prevention and control measures are adopted,the inflection point of the epidemic will appear soon,and the size of the basic reproduction number is crucial to epidemic control.Hubei Province has entered an inflection point about 10 days after the prevention and control is adopted,and the growth rate of the number of the exposed and infected persons will slow down faster,and the epidemic will be better controlled.The smaller the basic reproduction number,both the total number of infections and the peak number of infections will be greatly reduced,and the epidemic will be quickly controlled.Fifth,strict prevention and control measures are the key to controlling the epidemic.The number of infected cases when the latent is infectious will be nearly twice as many as when the latent is not.Therefore,strict prevention,control and isolation measures must be taken.The greater the isolation,the more comprehensive medical isolation and treatment,and the more personal protection measures are in place,the more conducive to controlling the epidemic.Sixth,at present,China is still facing great pressure on overseas input of the epidemic,and the focus of epidemic prevention and control should also be placed on“foreign input”.An assessment of the risk of overseas input of the epidemic in 30 provinces and municipalities in the mainland found that Guangdong,Jiangsu,and Shanghai are high-risk regions for overseas input of cases,and Shandong,Sichuan,Zhejiang,Beijing,Henan,Fujian,Shaanxi,and Hunan are medium-risk regions for overseas input of cases.And the remaining 19 regions are low-risk regions for overseas input of cases.Finally,based on the research conclusions,several policy recommendations are put forward,namely,to “regular epidemic prevention and control”,do well in security in six areas and stability on six fronts,accelerate the construction of a“domestic demand-oriented”demand structure,and build the new development pattern,support the development of new business formats such as the digital economy and promote the transformation and upgrading of industries.